This invention relates to diaminopyrimido-pyrimidine glycosides and glycotides and to methods for their synthesis. More particularly, this invention concerns the novel compounds, N.sup.4 -(2,3,5-tri-O-acetyl-.beta.-D-ribofuranosyl)pyrimido[4,5-d]pyrimidine-4,8- diamine and N.sup.4 -(5-O-phosphono-.beta.-D-ribofuranosyl)pyrimido[4,5-d]pyrimidine-4,8-diami ne, and an improved method or their production.
The aminoglycoside N.sup.4 -(.beta.-D-ribofuranosyl)-pyrimido[4,5-d]pyrimidine-4,8-diamine was produced initially as an "equimolar ammonia adduct" of ammonia and 6-cyano-D-ribofuranosylpurine by Ishido et al., Bull. Chem. Soc. (Japan), 40: 1007 (1967).
Berman et al., Tetrahedron Letters, No. 33, 3099-3101 (1973) investigated this reaction further and demonstrated that the "ammonia adduct" of Ishido et al. was N.sup.4 -(.beta.-D-ribofuranosyl)pyrimido[4,5-d]pyrimidine-4,8-diamine. The reaction sequence employed by Ishido et al. and Berman et al. for the production of this aminoglycoside involved the catalyzed high temperature reaction of 6-cyanopurine with tetra-O-acetyl-.beta.-D-ribose, followed by reaction with ammonia. The overall yield from this reaction, however is disappointing since yields from the first step are often of the order of 20%.
Burns, III, et al. demonstrated that the compound has broad spectrum antiviral activity, N. J. Burns, III et al., "Evaluation of a Novel Pyrimidopyrimidine Antiviral Agent," Paper No. A33, Abstracts of the 85th Annual Meeting, American Society for Microbiology, March, 1985. However, the compound is quite insoluble and its use as a pharmaceutical agent is thus impaired because of the attendant difficulties in delivering the compound in effective quantities to an organism.